In a semantic priming study, we investigated the processing of German-English homographs such as gift (German = "poison", English = "present") in sentence contexts using a joint reaction time (RT)/event-related brain potential (ERP) measure. Native German speakers with intermediate or advanced knowledge of English (N = 48) performed an all-L2 (English) experiment where sentences such as "The woman gave her friend an expensive gift" (control prime: item) were presented, followed by targets (i.e., boss) for lexical decision. To test the role of global task effects during sentence processing, we presented half the participants (N = 24) with a 20-min silent film narrated in German and half (N = 24) with the film in English before the experiment. To address the development of task effects over time, we analyzed the first and second blocks of the experiment. The results showed a significant interaction between semantic priming, movie version, and block in both the RTs and ERPs: there was significant semantic priming in the RTs and modulations in the N200 and N400 components only for participants who viewed the German movie, and only during the first block. Results suggest that in an all-L2 sentence task with L2 pre-task priming (English film), decision thresholds are raised high enough to eliminate measurable influence of the L1 on the L2. Despite identical material, participants who viewed the German film had to adjust, or zoom in, to the all-L2 task. Implications of this zooming in process in are discussed in terms of the recent Bilingual Interactive Activation (BIA+) model of bilingual word recognition [T. Dijkstra, W.J.B. Van Heuven, The architecture of the bilingual word recognition system: from identification to decision, Bilingualism: Lang. Cogn. 5 (2002) 175-197].